Telephone system.



No. 718,686. I I PATENTED JAN. 20, 1903.

1 F. B. WOOD.

TELEPHONE SYSTEM.

APPLICATION FILED AUG. 29, 1901.

N0 MODEL.

UNITED STATES ATENT FFICE.

FRANK B. WOOD, OF NEW YORK, N. Y., ASSIGNOR, BY DIRECT AND MESNE ASSIGNMENTS, TO FRANK B. WOOD, JR., AND CATHERINE WOOD, OF

NEW YORK, N. Y.

TELEPHONE SYSTEM.

SPECIFICATION forming; part of Letters Patent No. 718,686. dated January 20, 1 903. Application filed August 29, 1901. Serial No. 73,642. (No model T0 or whom, it may concern.-

Be it known that I, FRANK B. WOOD, a citizen of the United States, and a resident of New York city, borough of Manhattan, State of New York, have invented certain new and useful Improvements in Telephone Systems, of which the following is a specification.

My invention is particularly adapted for interior telephone service; and one of the objects of the invention is to enable the callbell or annunciator lines already installed in hotels and other buildings to be equipped with telephone instruments and accessories, so that with comparative minor alterations in the existing circuits a simple yet efficient telephone system may be established from various rooms or stations to the main office, which may be termed a central oflice; and to these ends the invention comprises the novel details of improvement that will be more fully hereinafter set forth and then pointed out in the claims.

My invention is illustrated diagrammatically in the accompanying drawing, wherein A B indicate'generally stations or rooms, of which there may be any appropriate number, and 0 indicates a main office or central station at which telephone and calling instruments are located.

1 2 indicate wires which lead from the stations or rooms A B to the central oliice and include annunciators or drops 1 2 thereat, and 3 is a common return-wire leading from central to the various stations and connected with the lines 1 2, and including a battery 1 and calling instrument 5. These wires may be the call-bell or annnnnciator wires already installed in a building to which my improvements are to be connected, although it will be understood that my improved system may be established independently of already-existing lines. In the wires 1 2 at central are located normally closed jacks 6, and a plug 7 is adapted to engage such jacks. The plug is provided with insulation 7 to break the normal circuit through the line-wires leading to the station. At the stations A B the lines 1 2 are normally open and are adapted to be closed by means of push-buttons or analogous switches 8 to operate the bell 5 at central.

In the example shown the telephone and other operating devices are installed at a box '9, and the wires 1 2 lead to binding-posts 10,

and for a purpose hereinafter explained I have shown two different arrangements at the stations A B for certain of the circuits; but for the purpose of calling central the binding-posts 10 are connected with a spring 8 of the push-button or switch 8, which is adapted to engage a contact 8 connected with a binding-post 11, that leads by a spur 3 to the common wire 3. From the foregoing it will be apparent that when either push-button is operated the instrument 5 will produce a call over the circuit including the lines 1 or 2 and 3, the battery 4:, and instrument 5, provided the jack is closed. These circuits may be the normal circuits of an existing installed call-bell or annunciator system. It will thus be seen that the alteration in such existing circuits is the inclusion therein of the jacks 6 and the boxes 9. In the boxes I have shown two forms of devices for calling any station or room desired from the main or central office O. In the box 9 at station B the contact 8* is connected with a metallic strip or plate 12, which connects with the binding-post 11 by a conductor 12, and adjacent to the strip 12 is acompanion strip 13, out of contact therewith, but in such close proximity thereto that an induced current may jump or pass from one to the other. The strip 13 is connected by a wire 14 with a binding-post 15, from which a wire 16 leads to one terminal of a receiver 17, and the other terminal of the receiver is connected by a wire 18 with a binding-post 19, from which a conductor 20 leads to binding-post 10. By this arrangement a call is produced by means of an induced current passing through the receiver 17, through the medium of the plug 7 and jack 6, and by the means hereinafter explained. The transmitter 21 is connected by a wire 21 with the hook or switch 22 of the receiver 17 in well-known manner, and said hook is adapted, when the receiver is removed therefrom, to engage a contact 23, that is electrically connected with the conductor 16, being shown in connection with the wire 14. The other side of the transmitter is connected with line 3, as by a wire 21 leading to binding-post 11. The talking-circuit at the box 9 at station B is thus established, as follows: from the wire 3 through 5, 11, 21 21, 21, 22, 23, 16, 17,18, and to post 10. In the construction shown at station A the line is fitted with a magneto and condenser instead of the strips or plates 12, 13, and in this case the magneto is connected by a wire 26 with binding-post 10 and wire 1 and with a condenser 27 with which the contact 8" is connected, the condenser being thus connected with post 11 and wire 3. Post 11 is also in this case connected by a wire 11 with post 15, and through 16, 17, 18 the circuit leads to contact 23, which is connected with post 19, the switch 22 being connected by wire 21 with one terminal of the trausmitterandthe other terminalof the transmitter being connected by a wire 21 withpost 10. Wire 2lorsaid postisconnected with contact 8 by a wire 8 \Vhen a call is to be produced at station A, an induced current goes through the magneto-bell 25 and the condenser 27 from 1 and over line 3, as hereinafter explained, and the talking-circuit at this instrument leads from line 3 through 3*, 11, 11, 16, 17, 1s, 23, 22, 21, 21, 21, and post 10 to line 1.

The devices at the main or central office O for transmitting and receiving calls and signals and for talking are arranged as follows:

30 is a box containing the mechanism and provided with a binding-post 31, from which a Wire 32 extends and is connected with wire 3 and includes a battery 33, the batteries 1 and 33 being balanced to prevent two or more talking-circuits from being established at the same time over wire 31 is a lever or arm having a contact 35, adapted to engagea contact 36, connected by a wire 37 with a battery 38, which is connected with the primary coil 39 of an induction-coil, such as a Ruhm korff or medical coil, said coil 39 being connected by a wire 10 with contact 35, so that when arm 31 is operated a local circuit for the battery 38 will be established through the coil 39. A spring 31 normally keeps the arm 31 raised to maintain said local circuitopen. The secondary coil 39 of said induction-coil is connected with a contact 11, adapted to be engaged by contact 12 on arm 31, a companion contact 11 being adapted to be engaged by contact 12 simultaneously with its engagement with contact 11, and the contact 11 is connected by a wire 13 with the hook-or lever 11 of the receiver 15. The contact 11 is also connected with the contact of plug 7, as by a wire 16. The opposite terminal of the secondary coil 39 is connected by a wire 17 with a magneto bell or instrument 18, that is connected with line 32, and thus when arm 31 is operated to close the circuit at 11, 12 of the secondary coil 39, at the same time closing the circuit of the primary coil at 35, 36, an induced current will flow to the station whose jack 6 has been connected with plug 7 through 11 and 16. The magneto-bell18 should be of a relatively high resistance, so that it will not operate at the same time the induced current jumps between the plates 12 and 13 or passes through condenser 27,0wing to the consequent reduction of the power of such induced current.

At the central station 0 the switch or arm 11 is held by the receiver 15 in normal engagement with a contact 50, that is connected with a contact 51, which, together with a companion contact 51, is normally in engagement with contact 12, and a line 52 leads from contact 51 through a drop 53 to a bell 51, which connects by a wire 55 with bindingpost 31. The wire 55 is also connected by a branch 56 with the transmitter 57, and from the opposite terminal of said transmitter a wire 58 leads to the wire 59 of the receiver 15, and the opposite terminal of the latter is connected by a wire 60 to a contact 61, adapted to be engaged by book or arm 11 when receiver 15 is removed therefrom for closing the talking-circuit at the central station.

The operation of my system may be described as follows: If the occupant of one of the rooms A or B desires to call central, he operates the push-button or switch 8 and establishes a circuit for bell 5 and annunciator 1 or 2, as before described. Suppose that a call has been received by central from station B. The attendant at central thereupon inserts the plug 7 in the corresponding jack 6, cutting out the drop 2, battery 1, and hell 5 and drawing down arm 31, forming a circuit from central to station B, as follows: from the plug 7 through wire 16, 11, 2, 11, coil 39, 17, 18, 32, 3, 3, 12, 12, across the space to 13, 11, 15, 16, 17, 18, 19, 20, 10, 2, and 6 to the plug 7. The circuit of coil 39 is now closed, and an induced current flows from coil 39 (whose circuit is now closed at 11, 11, 12) over the circuit just described, jumping the space 12, 13 and causing the diaphragm of receiver 17 to operate like an 01'- dinary electric buzzer to produce an answering-signal. At station A the answering-signal circuit would be through magneto 25 and condenser 27. By now releasing arm 31 and removing the receivers from their hooks the parties will be in telephonic communication. To call station B, the plug7 would be placed in jack 6, breaking the circuit of drop 2, and the arm 31 would be pulled down, thus breaking the circuit at 12, 51, 51, cutting out bell 51, and establishing the circuit for the primary coil 39 at 35, 36, and at the same time contact 12 will close the circuit at 11, 11, thus establishing a circuit for the induced current of coil 39 the same as above described for answering back. The receiver 17 at station 13 operates in the manner before described as a buzzer, while at the same time high-resistance bell 18 will not operate, as before explained. The occupant of room B would respond by operating the push-button 8, thereby establishing a closed circuit, which cuts out the receiver 17, at the same time thereby restoring the strength of the induced current from coil 39 by making a direct closed circuit through strip 12, whereupon the magneto-bell 48 operates by the full strength of the induced current, notifying the attendant at the central office that the party has responded to the call. The arm 34 is then restored to its normal position, cutting out the coil 39, breaking the local circuit of coil 39, and restoring circuit at 42, 51, 51 for the telephones. If telephonic connection were established with station A instead of with station E, according to the devices shown at station A, the

circuit would be substantially the same as that just described, excepting that at station A the circuit there leads from 3 through 11, 15, 16, 17, 18, 19 23, thence through 22, (the receiver 17 being removed from its hook,) 21", 21, and 21, to line 1, and thence through the jack and plug to the instruments at central. Should the operator at central leave plug 7 connected with a jack 6, the aununciator 1 or 2 at central would thereby be cut out, and to permit the occupant of such room nevertheless to produce a call at centralitis merely necessary for him to push his button 8, whereupon a circuit will be established through drop 52 and bell 54, as follows: from spring 8 through wire 2, 6,7, 46, 43, 44, 50, 51, 42, 51, 2, drop 53, bell 54, 55, 32, battery 33, line 3, to the station, thence through 3, 12 strip 12, and contact 8 to spring 8 again.

From the foregoing it will be understood that when call-bell or annunciator lines that have previously been installed in a building are to be utilized in connection with my system it is merely necessary to insert the boxes 9 therein at the stations, the jacks 6 at the central office, and connect the instruments of box 30 at central by a line 32 with the line 3, whereupon any desired number of rooms or other stations can be conveniently connected with telephone and calling instruments at central. It will also be understood that the plates 12 13 at station B and the condenser and magneto at station A are utilized as equivalents of each other in that they both operate with the induced current from coil 39 and that a system can be established with either one or both of such devices as may be desired. The advantage of using the plates 12 and 13, which are not in direct circuit, ad-

mits a direct line for the call from a station to central to be .used without including the receiver in the calling-circuit, while at the same time the receiver can be utilized for calling, and other calling instruments thereby dispensed with. On the other hand, the devices shown at station A enable the use of a magneto-bell for calling such station, while also permitting a direct line to be utilized for calling central independent of such magnetobell and independent of the receiver. It will also be apparent that by my system I am not obliged to run any additional wires beyond those already installed between the central office and the various rooms, whereby the eX- pense of installation of the system is reduced. My system also provides convenient means whereby the calling party may answer back to the central ofifice to indicate that he has received the call, and a further and very important ad vantage of my invention is that no matter how many rooms are connected on the common wire 3 no party on the system can cut in on the telephone-line and obtain current for their telephone instruments at the same time that another party is using the line, and thus listening over the line by different parties at the same time is prevented, as a separate and distinct circuit having current is provided for each room independent of any others. This is accomplished because the batteries 4 and 33 are balanced-that is to say, similar elements are opposed on the line. For instance, if a party at station B is using the telephone line and the party at another station, as A, removes the receiver from its hook, a circuit would be established for the latter station from 11 through 16, 17, 1S andthence through the transmitter and over line 1, through battery 4, to the branch wire 32, thence through battery 33 and through the telephone instruments at central over 46, the plug and jack, through the telephone instruments at station B to the post 11, and thence over line 3 back to post 11 at station A. In this circuit as similar elements of the batteries are opposed no current can be obtained for the telephone instruments at station A, and thus listening in is prevented. This secrecy is obtained by means of the Wire 32 at central, which passes around or cuts out the annunciators 1 2.

Having now described my invention, What I claim is 1. A telephone and calling system comprising a central office and stations, an independent line extending between central and each station, a common return-wire whose circuit is normally open at each station, means for producing calls at central from said stations, telephone instruments at said stations for connection with said lines, telephone instruments at central, a branch wire for connecting said telephone instruments at central with said-common wire, and means for connecting said instruments with either of the first-mentioned lines, substantially as described.

2. A telephone and calling system comprising a central office and stations, an independent line from central to each station including indicating instruments and jacks, a common return-Wire normally disconnected from each of said lines, a battery and signaling instrument connected therewith, circuit-closers in said lines for causing said instruments to operate, telephone instruments at said sta tions, means for connecting them with said lines, telephone instruments at central, a branch line connecting said instruments with said common wire, a battery for the telephone ICC instruments, and a plug connected with said telephone instruments at central and adapted to be connected with the jacks, substan-- tially as described.

3. A telephone and calling system com prising a central oflice and stations, lines extending between central and said stations, a common return-wire, a conductor connecting the latter wire with said lines and having a signaling instrument and battery, means for producing calls at central from said stations, telephone instruments at said stations for connection with said lines, telephone instruments at central, a branch wire for connecting said telephone instruments at central with said common wire, means for connecting said instruments with either of the first-mentioned lines, and means for sending an answeringsignal from central to the calling-station, substantially as described.

4. A telephone and calling system comprising a central olfice and stations, lines extending between central and said stations, a common return-wire, a conductor connecting the latter wire with said lines and having a signaling instrument and battery, a branch wire at central connected with said common wire and including a battery, signal-producing instruments at central connected with said branch wire, a plug connected with said instruments, jacks in the first-mentioned lines to connect with said plug, and means in the circuit of said instruments to break said circuit, substantially as described.

5. A telephone and calling system comprising a central office and stations, lines extending between central and said stations, a common return-wire, a branch wire at central connected with said common wire, signal-producing devices at the stations, an inductioncoil whose secondary coil is connected with said branch wire, a signaling instrument in the circuit of said secondary coil, a batterycircuit for the primary coil, jacks connected with the first-mentioned lines, a plug nor mally disconnected from the secondary coil, and a switch and contacts to close the circuit of the primary coil and the circuit of the secondary coil with said plug, substantially as described.

6. A telephone and calling system comprising a central office and stations, lines extending between central and said stations, a common return-wire, a branch wire at central connected with said common wire,signal-producing devices at the stations, an induction-coil whose secondary coil is connected with said branch wire, a signaling instrument in the circuit of said secondary coil, a battery-circuit for the primary coil, jacks connected with the first-mentioned lines, a plug normally disconnected from the secondary coil, and a switch and contacts to close the circuit of the primary coil and the circuit of the secondary coil with said plug, the circuit of a signal-producing device at a station having a pair of adjacent separated strips between which the current from the secondary coil will jump when said switch closes the circuit through the plug and jacks, substantially as described.

7. A telephone and calling system comprising a central office and stations, lines extending between central and said stations, a common return-wire, telephone instruments at a station whose receiver is connected with the line, a pair of adjacent separated strips in said line, a branch wire connected with said common wire, an induction-coil whose secondary is connected with said branch wire, a plug normally disconnected from the secondary coil, a switch and contacts to close the circuit of the secondary coil with said plug, a circuit and battery for the primary coil, and means to make and break said circuit, substantially as described.

8. A telephone and calling system comprising a central office and stations, lines extending between central and said stations, a common return-wire, telephone instruments at a station whose receiver is connected with the line, a pair of adjacent separated strips in said line, a branch wire connected with said common wire, an induction-coil Whose secondary is connected with said branch wire, a plug normally disconnected from the secondary coil, a switch and contacts to close the circuit of the secondary coil with said plug, a circuit and battery for the primary coil, means to make and break said circuit, a signaling instrument of relatively high resistance in the circuit of said secondary coil, and means at the station for forming a direct circuit for the last-named signaling instrument independent of the receiver, substantially as described.

9. A telephone and calling system comprising a central oiiice and stations, lines extending between central and said stations, a common return-wire,a branch wire at central connected with said common wire, signal-producing devices at the stations, an inductioncoil whose secondary coil is connected with said branch wire, a signaling instrument in the circuit of said secondary coil, a batterycircuit for the primary coil, jacks connected with the first-mentioned lines, a plug normally disconnected from the secondary coil, a switch and contacts to close the circuit of the primary coil and the circuit of the secondary coil with said plug, a signaling instrument of relatively highresistance in the circuit of the secondary coil, and means at the stations for forming a direct circuit for the last named signaling instrument independent of the signal-producing devices at the stations, substantially as described.

FRANK B. WOOD.

Witnesses:

T. F. BOURNE, J. M. GARDINER. 

